Benzodiazepine derivatives such as YF476 act as an antagonists at gastrin/CCK2 receptors (Semple et al. J Med Chem 1997; 40: 331-341).

Further benzodiazepine derivatives are described in WO93/16999, Yano et al. Chem Pharm Bull (Tokyo) 1996; 44: 2309-2313, Murphy et al. Clin Pharmacol Ther 1993; 54: 533-39 and Kramer et al. Biol Psychiatry 1995; 37: 462-466.
The synthesis of the type of benzodiazepine derivatives described in Semple et al. involves coupling of an isocyanate, for example 3-[N-(tert-butyloxycarbonyl)methylamino]phenyl isocyanate, with an amine, for example (R)-3-amino-1[(tert-butylcarbonyl)-methyl]-2,3-dihydro-5-(2-pyridyl)-1H-1,4-benzodiazepin-2-one. The isocyanate is prepared using potentially explosive azide chemistry.
There remains a need for improved synthetic processes for the production of this type of benzodiazepine derivatives which avoid the need for potentially explosive azide chemistry. In addition, there remains a need for efficacious gastrin/cholecystokinin 2 (CCK2) receptor antagonists which can successfully be used in pharmaceutical compositions to provide beneficial properties in terms of pharmacokinetics, improved bioavailability, avoidance of a requirement for administration with food, minimisation of processing steps required in formulation, and the like.